The invention relates to a pyrotechnic smoke kit for generating a smoke screen.
Such a pyrotechnic smoke kit is known from DE 3728380 C1. The smoke kit is a mixture of a light-metal powder, preferably magnesium powder, as the metallic reduction agent; potassium nitrate or a mixture of potassium nitrate and potassium perchlorate as the main oxidation agent; at least one carbonate, such as calcium carbonate, potassium hydrogen carbonate, sodium hydrogen carbonate, potassium carbonate or sodium carbonate as a further auxiliary oxidation agent; substances splitting off nitrogen as combustion moderators; as well as potassium chloride as sublimable substance and/or a common salt as evaporable non-toxic smoke-forming substance.
Azodicarbonamide, oxamide or dicyandiamide are preferably used as substances splitting off nitrogen.
The mixture of said substances is preferably pressed into a casing at whose end an ignition mixture is provided. The ignition mixture consists substantially of the same components as the smoke kit, however, with the exception of the combustion moderators, but has a changed quantitative composition as is explained in detail in the patent specification.
This known pyrotechnic smoke kit proved its excellent worth. However, it turned out that this mixture is susceptible to corrosion in the case of very long storage times. The metal contained in the smoke kit reacts with water that is present as residual humidity in the smoke kit or originates from the environmental humidity, hydrogen being formed. The released hydrogen reduces the nitrate in the smoke kit to gaseous ammonia which weakens the structure of a smoke body contained in the smoke kit already due to the increase in volume accompanying the formation of gaseous ammonia. After a longer storage time it may happen that the pyrotechnic smoke kit is no longer efficient to an optimum degree.